Machine for sizing and finishing bores



April 18, 1939. H. w. ZIMMERMAN MACHINE FOR SIZING AND FINISHING BORES Filed Feb. 8, 1936 6 Sheets-Sheet 1 April 18, 1939. H. w. ZIMMERMAN MACHINE FOR SIZING AND FINISHING BORES Filed Feb. 8, 1936 6 ShebS-Sheet 2 April 18, 1939. H. w. ZIMMERMAN MACHINE FOR SIZING AND FINISHING BORES Filed Feb. 8, 1936 6 Sheets-Sheet 3 N%\ QQ @www H. W. ZIMMERMAN MACHINE FOR SIZING AND FINISHING BORES April 1s, 1939.

Filed Feb. 8, 1936 6 Sheets-Sheet 4 H. w. ZIMMERMAN 2,155,072 l MACHINE FOR SIZING AND FINISHING ORES April 18, 1939.

6 Sheets-Sheet 5 Filed Feb. 8, 1936 M bbw.

QM., QN

v April 18, 1939. H. w. ZIMMERMAN MACH'INE FOR SIZING AND' FINISHING BORES 6 Sheess-SheefI 6 Filed Feb. 8, 1936 Patented Apr. 1939 UNITED .STATES 2,155,012 MACHINE Fon. srzlNG AND FmsmG norms lerman W. Zimmerman, North Chicago, Ill., as-

signor to Automotive Maintenance Machinery Co., North Chicago, Ill., a corporation cilllinois Application February 8,1936, Serial No. 62,904 16 claims. (ci. 51.-'12) My invention relates to a machine for sizing and finishing bores and it has to do more particularly with a structure adapted for supporting and operating tools for treating bores and '5 especially, though not exclusively, small bores, such as those employed for piston pins, water pump bushings, hydraulic brake cylinders and king bolt bushings.

One of the objects of my invention is to prom vide a machine of the foregoing character that is arranged for detachably supporting different kinds of bore treating tools (for example honing and roaming tools) and -for selectively operating the same at variable speeds dependent upon the il character of the work and the kind of tool used thereon.

Another object is to provide an improved honing machine including -novel means for automatically adjusting the tool during operation and 20 lWithin preset, but variable, limits. A further object is to provide, as a single selfcontained unit, means for supporting different kinds of bore treating tools, means for driving such tools at variable speeds, and means for automatically adjusting the tools during operation within predetermined limits, all such means being interlockingly and cooperatively arranged i'n a compact form that is readily portable.

Still another object is to provide power driven structure of the foregoing character which is quite simple'in construction; is inexpensive to manufacture, operate and maintain in use; is easy to operate; and is adapted for very rapid bore treatment with increased eiliciency even 3l when used by unskilled workmen.

An additional object is to provide an improved chuck structure for centering and attaching tools to the machine.

Other objects and advantages will become apparent as this description progresses and by reference in the drawings wherein- Figure lis aside elevational view of one form of machine embodying nLy invention and to which a hone or finished tool is attached. certain of the Y4l machine parts being illustrated in dotted unes in an inactive position such as they may assume when the honing tool is in fulLv contracted condition:

Fig. 2 is an enlarged longitudinal vertical sec- I0 tional view of the structure shown in Fig. 1;

Figure 3 is a horizontal sectional view taken at a position near the top of the machine;

Fig. 4 is a section taken substantially on the line Ir-Ii of Fig. 3; Fig. 5 ts a'skeleton-like view of the adjustment mechanism shownin Fig. 1, the parts of such mechanism being illustrated in positions that they may assume when the tool is inserted within the bore to be honed and then expanded into operative engagement therewith;- 5 y Fig. 6 is an enlarged vertical sectional view of the structure shown in Fig. 2, which gure is taken substantially on line 6-6 of Fig. 2;

Fig. '7 is an enlarged front elevational view of the adjusting dial structure shown in Figs. 1 l0 and 2; f I

Fig. 8 is a front elevational view of one form of my improved chuck structure, such as may be used for example for supporting a reamer at the right-hand side (as viewed in Fig. 3) 'of the l5 machine;

Fig. 9 is a section taken substantially on line 9 9 of Fig. 8;

Fig. l0 is a section taken substantially on lin IU-Ill of Fig. 9; 1 l -20 Fig. 11 isa section taken substantially on line II--II of Fig. 9; y

Fig. 12 is a front elevational view of the chuck body member shown in Figs. 8 and 9; and

Fig. 13 is a detached perspective view 0f one 25 of the checkjaws used in connection' with the structure shown-in Figs. 8 to 12, inclusive.

A machine constructed in accordance with my invention is well suited for the automotive servicev field for the servicing of piston pin mount- 30 ings, water pump bushings, hydraulic brake cylinders and king bolt bushings, but it is to be understoodl that it has utility in every instance where the advantages thereof are sought. In the servicing of parts of the character above men- 35 tioned, it is found desirable at times to merely hone the same and at other times tov first ream the bore'and then nish the teamed surface by honing. My invention provides astructure by which either or both of these operations may be 4 carried out with a single device, which device is selectively operable to-provide speed changes such as may be required by the particular kind of work and the particular kind of tool employed.

'The ,machine that I have chosen to illustrate 45 my invention comprises a somewhat shallow'and rectangularly-shaped casing 20 in which is mounted a speed-change type of driving mechanism power driven by a motor 2l (Fig. 1) through a belt and pulley construction 22, '23 50 (Figs. 3 and 4) llhe casing 20 supports another and L-shaped casing 24 in which is mounted tool adjusting mechanism which will be described more fully hereinafter. The vertical leg 25 of the casing 2l 55 is secured to the re'ar wall oi' thev casing '23 by bolt and nut devices 25 (Fig. i),eand therhorizontal leg of thisgcasing above the top of the casing 23.

.The speed-change drivingl or transmission mechanism (Figs. 2, 3 and 4) housed within the casing 23 includes a rotatable shaft 21 having the pulley 23 secured to the outer end thereof by a lock screw, or the like, 23.( This shaft 21 finds bearing support in a bossfl formed in one end of the casing 23 and it extends through the casing where it is rotatably supported within the shank 30 of a chuck device 3| which, in turn, is rotatably supported in a boss 32 formed in the other end wall of the casing 2|)v directly opposite the boss 29. The shaft 21 supports similar sized sprocket wheels 33 and 34 having hubs 35 and 35 rigidly secured thereto by pins or other suitable devices 31. The sprocket hub 35 and a hub 38 on the pulley 23 engage opposite ends of the boss 29 and thereby secure the shaft 21 rotatably in its bear- -ings against longitudinal displacement.l

The driving mechanism further includes, at the other side of the casing 23, a rotatable shaft 39 (Figs. 2 and 3). This shaft 39 is somewhat T- shaped in longitudinal section with its T-head end portion 43 projecting beyond the forward pin, or the like, 45 so that the shaft 39 may be rotatably supported by the bosses 42 and 43 without endwise displacement. The shaft 39' (Fig. 2) is hollow for reception of part of the adjusting mechanism which will be described hereinafter.

The shaft 39 supports sprocket wheels 45 and 41 (Figs. 2, 3 and 4) which have hub portions 43 and 49, respectively, mounted for free rotation ,upon such shaft. 'I'he sprocket wheels 33 and 45 are drive-connected by a sprocket chain 50 while the sprocket wheels 34 .and 41 are drive-connected by a sprocket chain 5| so that the sprockets 45 and 41 are rotatably driven upon their shaft 39 when the pulley-supporting shaft 21 is rotated.

lThe shaft 39 also supports a sprocket wheel 52 (Figs. 2, 3 and 4) having a hub 53 ilxedly secured thereto for rotation therewith in anydesired manner. The sprocket wheel 52 is connected to another and intermediate sprocket 54 by a sprocket chain 55. The sprocket 54 is providedwith a hub 55 rotatably mounted in any desired manner upon a shaft 51 having its ends Isupported infbosses 53 and 59 at the opposite ends of thecasing 23. 'Ihe sprocket hub 53 also supports `a` sprocket 53 and this sprocket is connected by a sprocket chain 52 to a sprocket 53 xedly secured to the hub 30 of the chuck device 3|.

The bottom portion of casing 23 serves as an oil reservoir. This casing is provided with a false bottom 2|)a to locate the bottom wall in close proximity to the speed-change gearing soI that a minimum depth of oil may be used. The oil level is indicated in Fig. 4, and it is such that only the larger sprocket 41 and its sprocket chain 5| move therein. 'I'his arrangement causes suiljlcient splashing and throwing of oil to properlyl lubricate the other moving parts within the casing 2n. on 1e admitted te, and the level thereof determinedlbyoil cup 23h at one side of thcanemia' at hand. The chuck device 3|. in the particular machine disclosed, is adapted, preferably, to support a reamer device which is desirably rotated at-'a lower speed than the honing device. speed differential is accomplished through the sprocket gearing above described and, particularly, by employing a sprocket'45 of sumcient size to normally rotate the shaft 39 and honing device 54 at, for example, approximately 500 revolutions per minute, while the sprocket 41 is of larger size and adapted, comparatively, for speed reduction of t e shaft, and rotation of the honing device, to approximately 300 revolutions per minute. A clutch device 55 (Figs. 2, 3 and 6) is employed for selectively connecting the sprockets 45 and 41 to the shaft 39. The reamer device (not shown) and its chuck 3| are rotatably driven from the shaft 39 through sprockets 52, 54, 50 and 53 and their drive sprocket chains 55, and 52. The sprockets of Athis latter drive structure are of a character adapted for speed reduction so that, for example, when the shaft 39 is driven through the sprocket 45, the reamer will be rotated at approximately revolutions per minute and .when the sprocket 41 is connected to the shaft 33. the speed of reamer rotation will be reduced to about 54 revolutions per minute. It is to be understood that the speeds andthe speed change relationships above mentioned may be varied to suit particular conditions of use.

The clutch device 55 (Figs. 2 and 6) includes a clutch body 55 having enlarged circular end flanges 51 defining an annular groove 53. The

clutch member 55 is provided with an axial opening of suiiicient size to snugly receive a bushing 59 rigidly secured to the shaft 39 by screws or pins 10 (Fig. 6), and there is a spline connection 1| between the c lutch member 55 and bushing '59 that permits axial slide movement of the clutch member over the bushing while positively connecting the clutch member for rotation with the shaft 39. Movement of the clutch to the left, as viewed in Fig. 2, connects the same with the sprocket 45 for high speed rotation, and movement of the same in an opposite direction connects it with the sprocket 41 for lower speed operation. The connection between the qlutich member and the sprockets 4,3, 41 is accomlplished by radially-directed slots 12 von the clutch member flanges that are interlockingly engaged or meshed with laterally-extending lugs 13 secured by riveting, or otherwise, to the faces of the sprockets 45 and 41 adjacent to the clutch member 55.

'Ihe clutch 55 is manually actuated by a handle 14 (Fig. 4) securedto the end of a shaft 15 rotatably mounted inA the casing 23.- The inner portion of the shaft 15 supports an upstanding yoke member 15, the arms 1.1 of`which support pins 13 that engage in groove 53 of the clutch member.

When the clutch member 55 is moved to the left (Fig. 2) through its handle 14 and the slotand-pin connection 58, 13, the sprocket 45 is positively connected to the shaft 39jso that such shaft is directly rotated from the power source through the shaft 21; and when the clutch memably provided in the end plates 80, 8|.

ner edges of the carrier members 94 are provided andere ber is shifted in the opposite direction the shaft 39 is driven through the sprocket I1 with a speed reduction as above explained. When the shaft 39 is rotated the reamer chuck 3| is likewise rotated, but at a reduced speed,' through the sprockets 52, 54, 60 and 53; andthe speed of the chuck 3| and the tool carried thereby may be varied by shifting the clutch member '65 to connect one or the other of the sprockets 45 and 41. If desired, the clutch member may be moved by its handle 14 to a neutral position, in which case the shaft 39 and the tool or tools driven thereby remain at rest. If desired, means (not shown) may be provided for positively holding the handle in that as well as the other positions.

The honing device 64 preferably takes the form shown in Figs. 1 and 5, which is quite similar to the hone shown in my Letters Patent No. 1,936,612, granted on November 28, 1933. This hone includes end members and 8| rigidly connected together by annularly spaced posts 82. 'Ihe end members 80, 8| are provided with radial grooves 83 which. support the end portions of radially expansible and contractible carrier members 8l that support an abrading material 85 for honing purposes. Expansion of the carrier members 8l is accomplished by coneshaped spreaders 8B iixedly secured to a stem 81 supported for axial shift movement in bores suit- 'Ihe inwith notches 88 that are shaped complementally t5 the cone spreader surfaces with which they engage. When the adjusting stem 81 is moved in one direction (to the right in Fig. 5) the tool is expanded, and when it is moved in the o pposite direction, spring rings 89 encircling the opposite exterior end portions of the carrier members 84 contract the tool. 4

'I'he honing device 5l is provided with elongated and hollow drive shaft 90 (Figs. 1 and 5) .which, preferably, takes the form of an extension. of the end plate 8|, although this shaft may be connected with the honing tool frame in any suitable manner so as to drive the latter rotatably. The outer end of the shaft 90 is provided with an enlarged head 9| secured thereto by one or more locking screws or pins 92. The head 9| is of such shape as to constitute a T-'shaped drive extension for the'shaft 90, and the T-head portion of the shaft 39 is provided with a similarlyvShaped socket 93 in which the head 9| is re ceived. The head 9| is drive connected in the socket 93 by a-bayonet slot-and-pin connection 94 (Figs. 3 and 5) soi that the honing device may be readily detached from the driving mechanism. In this way, the hone is directly driven by the shaft 39.

In Pig. 5, I have illustrated the hone as applied to, and expanded into operative engagement with the Wa11.95 of a bore such, for example, as a piston pin hole. 'I he tool is aligned with bore 95 by a cone-shaped guide 96 slidably mounted upon the hone shafe 90 having its cone surface adapted to engage the outer and squared end surface of the bore to be honed. To insure proper and constant engagement of the c one device with the work, I mount a spring 91 around the shaft 90, with. one end of this spring received in a recess 90 in the cone guide 99 and its other end received in a recess 99 formed in the adjacent shank portion of the drive head' 9|. The

spring 91 is normally confined under slight compression between the head 9| and guide 99 and, in pperation, with the guide 96 engaged with the work, the spring will be further compressed and it will hold the guide 90 in proper position' under the control of the automatic expansion means.

In carrying out the foregoing feature, the hone adjusting shaft 81 is of suilicient length to extend i through the hone driving shaft 90 to substan- The outer part of the opening |00 in shaft 99 is somewhat larger' .than the adjustment shaft 81 and the remainder tialiy the outer end thereof.

of such openingis such as to provide a' rather snu secur to the outer endof the shaft 81 and it is adapted to t slidably within the-enlarged part of the opening |00. A spring |02 is mounted upon the shaft 91 within the opening |00 and it is confined therein normally under tension by the 'Ihe spring |02 constantly tends to move the adjusting stem 81 in a direction to contract the tool so that when the'tool parts are released for contraction such action will be rapidly and positively carried out.

The adjustment shaft 91 is moved in tool expension directionby adjustment mechanism including a shaft |03 passing slidably through an opening in the tool drive head 9| and having a sleeve |04, similar to the sleeve |0I, slidably received within the shaft 90 and normally in engagement with the adjacent end of the adjusting shaft 81. The short shaft |03 is, in turn, engaged and actuated in axial direction by another shaft |05 slidably supported within `the drive shaft 39'; The shaft |05 has its rear end portion projecting beyond the -rear endof the shaft 39 where it engages an arcuate pad-like portion' |09 of an arm |01 hingedly supported at its lower end by a pin |08 carried by the casing 25 (Figs. 2 and 5). The

upper end of the arm |01 is free and this arm is constantly urged in forward direction against the end of shaft |05 by a spring |09 having one slide fit for the shaft 81. A sleeve |0| is 30 end received in a recess ||0 (Figs. 2 and 5) in the rear part of the arm |01. The other end of spring |09 is guidlngly seated upon a flange H5 at the inner end of an 4adjusting screw, in screwthreaded engagement with a rear, socket portion ||2 of the casing 2l. The screw is provided. I

with a knurled adjusting wheel I3 xedly secured thereto by a pin IH. 'I'he spring |09 is of greater strength than the spring |02 so that the tool parts are normally moved in an expanding direction.

The spring |89 is normally of sufiicient length and under' such tension as to yieldably movethe arm |01 throughout a certain range of expanding movement, and to also apply sumcient expanding pressure to effect a predetermined engagement between the honing\device and the bore being honed. By rotating the screwdevice I in clockwise direction the tension of the spring |09 may be increased to increase the pressure of the hone against the bore. 'Ihis is a desirable feature accommodating the finishing of various kinds of bore surfaces and it tends to increase the speed is 'transmitted to the adjusting shaft 81 through the shaft connections o'r members |05 and |03 so that the tool is expanded. As the honing operation is carried on, the spring |00 gradually and continuously expands the tool to a predetermined extent. 0

When the honing tool is not in operation, and for the purpose of facilitating application of the tool to thework, I provide means for moving and latching the arm |01 against expanding action so that the tool contracting springs |02 and 30 are permitted to contract the tool. Specically, I employa pair of swingable arms ||0, ||1 (Fig. 5) mounted in somewhat vertical offset relation upon shafts ||0 and ||9 rotatably carried in any suitable fashion by one of the walls of the casing 24 (Fig. 4). The arms ||6 and lll are connected together for simultaneous swing movement by link |20, swingably connected thereto by pins |2 I |22. This arm-and-link structure is adapted to be swung rearwardly and forwardly by a handle |23 secured to an end of the shaft ||3 projecting through the wall of casing 24.

As the link and arm structure |8|20 is swung rearwardly, the upper end of the arm |01 is moved rearwardly for contraction of the tool. More particularly, the link-connecting pin |22 is extended laterally opposite the arm |01, and this pin, when the arm and link structure is swung rearwardly, engages the arm |01 to move it rearwardly. The arm I6 may be moved sufiiciently to throw it past the center of shaft ||0 (Fig. 2),

' at which time the extension of pin |22 is engaged `notch |24 and free the arm |01 for forward expanding movement.

To limit the expanding' and honing action of the tool, I provide the stop structure shown in Figs. 2 and 5. Specifically, the structure illustrated includes a stop stem 25 slidably supported by a hanger-type boss |26 carried by the casing 24. 'Ihe stem |25 projects into the path of the upper pad-like end portion |21 of the arm |01 and limits the forward movement of such arm. '111e stem |25 is arranged for longitudinal adjustment so as to yvary/the extent of forward movement of the arm |,01 and, in turn, extent of the hone expansion. To this end, the forward end of the stem |25 is rigidly connected, as by a pin to asleeve-like member |20 having an enlarged central bore and a slightly reduced threaded opening in its forward end in whichl a screw stem |30 is threadedlyreceived. The enlarged portion |3| of the sl'eevebore permits free movement of the screw |30' within the sleeve member |29 so that screw-adjustment operation may be accomplished with ease. The sleeve |20 and stop stem are prevented from rotation by a casing-carried screw member |32 having its inner end portion slidably received within a slot |33 in-the upper or adjacent portion of the sleeve |20. The screw stem is rotatably supported within a bushing |34 locked by a screw |35 within a boss portion |30 in the upper forward portion displacement as itis rotated.- The dial member |30 (Fig. 7) is provided' with graduations |42,v

each of which may representY any desired amount 0 of expansion in the-honing tool. This dial mem ber is also set into a shallow recess formed in the adjacent wall of casing 24 so that graduations |42 may register flush with an indicating mark '|43 above the dial member on the casing wall.

In' the operation of the stop mechanism, rotation of the adjusting device |31. in .clockwise direction moves the stop stem |25 forwardly to increase the expansion range of the arm |01, and vice Iversa, when such device is rotated in counterclockwise direction. By. way of example, assuming that it is desired to remove '.001 inch of material from the work, the contracted tool may be inserted in the work, after which the tool is permitted to expand into firm engagement .end |21 of the arm m1. At that time one or the dial member graduations will register with or have a certain relation tothe mark |43. l'I'he adjusting device is then rotated in clockwise direction an extent corresponding to that required to remove .001 inch of material from the work. As the honing action is carried on, the tool being constantly vexpanded under the influence of spring |09, the arm |01 will eventually move into engagement with the end of the stop stem |25 and, although the drive of the tool may be continued, the honing action will be discontinued because the tool cannot. expand further. In compensation for wear of the abrasive material of the honing device, the dial member may be rotated a short additional extent afterthe stop stem is engaged as described and the honing operation continued untii movement of the arm |01 is again stopped. In this way, the work may be honed with great accuracy and without danger In the use of a reamer device in connection with power-driven structure of this character, it is essential that 'such device be rigidly and securely supported. It is also desirable that such device be readily and quickly detachable, as well as foolproof with respect to proper` centering and supporting actions. I, therefore, employ a novel chuck device, one form of which is found in the chuck 3| (Fig. 3). Specifically, this particular form of my invention includes a cup-shaped chuck body 'having a reduced hollow extension adapted to be rotatably received inthe boss 32 of the casing 20 and also arranged to rotatably receive the shaft 21. The chuckbody is provided with a cylindrical opening |5| and upper, and lower diametrically opposed slots |52, |53 are provided in its wall for snug, slidable reception of chuck jaw membersv |54 (Figs. 10 and 13). vThese j w members are movable toward and from' ea h other to engage and release the tool to be held thereby, the facing surfaces of the jaw members being provided with notches |54* to receive and hold the shank of such tool.

'I'he jaw slots |52, |53 extend entirely through the wall of the chuck body and outward movenient of the jaws |54 is normally limited by a ring |55 having its lower and forward edge beveled or cut away at an angle to engage a complementally-shaped outer wedge-shaped surface :soA

engagement with the 'ring |55 by a spring |58 mounted in a comparatively narrow and yrectangularly-shaped recess |59 in the inner bottom portion of the chuckf'body. The opposite ends of the spring |58 are engaged within the reduced rear ends or tongues |60 on the chuck jaws which slidably fit within the correspondingly-shaped spring-receiving recess |59. The

29 chuck surfaces just described cooperate with the walls of the recess |59 andthe bottom of the chuck body to hold the jaw members |54 against cooking and in squared alignment for properly receiving, centering and holding the tool. 22?? The front ends of the jaw slots |52, |53 are closed by a plate member |52 secured to the front end of the chuck body |55 by screws, or other suitable fastening devices, |83. The central portion of the plate member |52is provided $9 with a rectangular opening |84, the walls of which are arranged parallel withthe adjacent walls of the jaw notches |54, The opening |54 4permits the ready insertion of the shank of the Y tool to be held by the jaw members |54. 35 In the use of the chuck structure just described,

the adjusting nut |55 is adjusted rearwardly, freeing the jaw members |54 for movement of the same to an expanded position by the spring |55, as illustrated in Figs. 8 and 9. 'I'he shank of the tool to be held by the chuck is then inserted through the opening |64 andinto alignment with the jaw notches |54, whereupon the nut |55 is screwed forwardly. in turn moving the ring |55 forwardly along the tapered wall of the jaw members, causing the latter to move inward into contracted holding engagement with the tool shank. In this way the tool is securely held in properly centered relation with respect to its driving mechanism and it will be Vretained in that condition until the nut |56 is adjusted to release the same.

I believe that the operation and advantages of my invention will be readily understood from the foregoing. When it is desired to first ream and then hone a piece of work, the proper size reamer (the chuck device 3| accommodating different size reamers) is secured in the chuck device 9|, and if the character of the-materialto be teamed is such as to require high-speed reaming operation, the clutch device 55 is moved to cut in and drive the transmission mechanism throurh the sprocket 46. If the material worked upon is 'of such a character as'to require a lower speed, the clutch device 55 is moved to cut in the sprocket 41. After the reaming operation has been completed, the work is removed from the reamer and it is then applied to the honing device, which is adjusted thereto as hereinabove described. The clutch device 'is then actuated for high or lower speed operation, as above 'mentioned. Either reaming or honing operations alone may be carried out or, if'desirable, both reaming and honing operations upon 'diiIerent pieces of work may be carried out simultaneously.

It is to be understood that, although I have shown and described only one form of structure embodying my invention, changes 'in details and arrangements of parts may be made therein without departing from the spirit and scope of my. invention as dened by the claims that follow.

l. In structure of the class described, a power driver, a shaft rotatably driven by said driver, a second shaft, speed-change driv'e connections including manually operable clutch means between said first and second shafts, a tool supporting member carried directly by and driven by said second shaft, a second tool supporting member, and speed reducing drive connections between said second shaft and said second tool supporting member whereby said second tool supporting member is driven at speeds different from the respective speeds of said first tool supporting member.

2. In structure of the class described.. a power drive, a shaft driven thereby, a second shaft, a tool supporting member carried by and driven by saidsecond shaft, a pair of gear members fixed on said rst shaft, a pair of gear members rotatable on said second shaft and of different sizes for speed-change purposes, means driveconnecting the gears on said first shaft with the gears on said second shaft, respectively, clutch means rotatable with 'said second'shaft and shiftable to engage one or the other of said gears on said second shaft, a second tool supporting member, and speed reducing drive connections directly between said second shaft and said second tool supporting member.

3. In structure of the class described, an expansible tool, and means for rotatably driving and expanding said tool which includes an elongated hollow driven shafton said tool, a tool expanding shaft passing through said hollow driven shaft, a tool driving shaft detachably connected to said driven shaft, drive connections on said drive shaft, another tool expanding shaft in said drive shaft normally engaged with said rst expanding shaft 4and extending through and beyond said drive shaft, spring urged means engaged with the extending part of said secondmentioned expanding shaft and urging said expanding shafts in tool expanding direction while said shafts are rotated, and spring means of reduced strength acting directly upon said rst expanding vshaft and yieldably opposing expanding movement of said expanding shafts.

4. In structure of the class described, an expansible tool, and means for rotatably driving and expanding said tool which includes a hollow driven shaft attached to saidtool, a hollow and axially aligned driving shaft detachably connected at its forward end to said driven shaft,

i and expanding said tool which includes va hollow driven shaft attached to said tool, a hollow and axially aligned driving shaft detachably connected at its forward end to said driven shaft,

means including drive connections on said driving `shaft for rotating both said 'shafts and tool, a sectional tool expanding shaft extending through both said shafts and projecting from the rear end of said driving shaft, spring means in said hollow driven shaft engaging and urging said expanding shaft in contractingdirection,

stronger spring means urging said expanding shaft in expanding direction, and means posi-- tively limiting the extent of movement of said expanding shaft in expanding direction.

6. In structure of the class described, an expansible tool, and means for rotatably driving and expanding said tool which includes a hollow driven shaft attached to said tool, a hollow and axially aligned driving shaft detachably connected at its forward end to said driven shaft, means including drive connections on said driving shaft for rotating both said driving andl driven shafts, tool expanding and contracting means including a sectional expanding shaft extending through both said drive and driven shafts, the arrangement being such that part of said expanding-shaftds retained in said driven shaft and part in sdm dnvingsnsft when ssid latter shafts are detached from each other means including a spring-actuated member for urging said expanding shaft in expanding direction, and means for moving said member away from said expanding shaft to permit contraction of the t`ool.

"7. In structure of the class described, a tool including carriers mounted for expansion and contraction movements, means engaged with said carriers for expanding and contracting the same, and means for actuating said first means including an elongated shaft, spring means urging the tool parts in contracting direction, stronger Aspring means including aspring-actuated member swingably mounted for movement toward and from said shaft for moving said shaft and carriers in expanding direction, means operable at will for holding said member against movement toward said shaft. and means adapted to be engaged by said member for limiting the extent of expanding movement of said shaft when said member is released from said holding means.

8. In structure of the class described, a tool including carriers mounted for radial expansion and contraction movements, means engaged with said carriers for expanding and contracting the same,and means for actuating said first means including an elongated shaft, a spring constantly urging said shaft in. contracting direction, stronger spring means including a.v shiftable member lfor constantly urging said shaft in expanding direction, and means for relieving the action of said stronger spring means and permit,- ting said other spring means to move said shaft in contracting direction, including a manually operable member movable to engage and shift said iirst member to an inactive position.

il. In structure of the class described, a tool including bore treatment members mounted for radial expansion and contraction movements, means engaged with saidmembers'for expanding and contracting the same, and means for. actuating said first means includingan elongated shaft connected -to-said rst means, an arm en- 8981118 the end of said shaft opposite said tool,

a spring urging said arm toward said shaft to v ing said spring inactive, means for adjusting the` tension of said spring, and stop means for limiting the extent of expanding movement of said arm.

10. In structure of the class described, a tool including bore treating members mounted for radial expansion and contraction movements, means engaged with said members for expanding and contracting the same, spring means yieldably holding said members engaged with said first means, and means for actuating said first means including an elongated shaft, a spring acting independently of said spring means for constantly urging said shaft in contracting direction, van arm engaging the end of'said shaft opposite said tool, a spring stronger than said rst spring constantly urging said arm toward said shaft tending to expand the latter, means for adjusting the tension of said stronger spring, and adjustable stop means for variably, limiting the extent of movement o f said arm toward said shaft.

11. In structure of the class described, a honstronger than said first spring constantly urging said arm toward said shaft, and means for moving said arm away from said shaft permittingsaid rst spring to move said shaft in tool contracting direction.

. 12. In structure of. the class described, a tooly including borev treating members mounted for radial expansion and contraction movements. means` engaged with said members for expanding and contracting the same, and means for actuating said first means including a shaft, an arm engaging the end of said shaft opposite said tool, a spring urging said arm and shaft in tool expanding direction, means urging saidshaft in a contracting direction, and means for moving said arm awayfrom said shaft and for latchlng it in'a position wherein said shaft is moved by saidcontracting means to and held in a contracted position.

13. Mechanism for adjusting an expansible and contractible tool of the class described, which includes a shaft shifts-ble in one direction to expand the tool and shiftable in the opposite direc-. tion. to contract the tool, spring means constantly urgingsaid shaft'in contracting direction, an arm engaging said shaft, a spring stronger than said nrst spring acting on said ann and constantly urging it in a direction to move said shaft in expanding direction, means limiting the extent of expanding movement of said 'ann and shaft, and independent means for relieving the pressure of said second spring permitting said first spring to move said shaft in contracting direction. y

14. Mechanism for adjustingan expansible and contractible tool of the class described, which i includes an elongated shaft shiftable in one direction. to expand the tool and shiftable inthe opposite direction to contract the tool, spring means urging said shaft in contracting direction, an arm pivotally .supported at one end and engaging said shaft, a spring stronger than said first spring acting on said arm and constantly urging it in a direction to move said shaft in expanding direction, means disposed in` the path of the other end of said` arm and adjustable for variably limiting the extent of expanding movement of said arm and shaft, and separate means for moving said arm away from said shaft to permit said first spring to move said shaft to a tool contracted position.

15. Mechanism for adjusting an expansible and contractible tool of the class described, which includes a shaft shiftable in one direction to expand the tool and shiftable in the opposite direction to contract the tool, spring means urging said shaft in contracting direction, an arm en*- gaging said shaft, another spring acting on said arm and constantly urging it against the pressure of the iirst spring in a direction to move said shaft in expanding direction, means for moving saidarm away from said shaft therein7 relieving the pressure of said second spring permitting said mst spring to move said shaft in contracting direction, and means for latching and holding said arm in a pressure-relieving position as desired wherein said first spring is free to move said shaft to a fully contracted position. l

16. In structure of the class described, power drive. means, a rotatable member driven by said power drive means, an adjustable tool member directly supported by vsaid rotatable member, a second rotatable member, a. tool supported by said second rotatable member, means by which said second rotatable member is driven by said first rotatable member, means associated with said iirst rotatable member and engaging said rst tool for adjusting the latter, and means for g at will the speed of rotation of said rotatable members without changing the speed of said power drive means. 

